Question: Expand.
$\begin{aligned} &\phantom{=}({3a^2-1})(-3a^2+5) \\\\ &={3a^2}(-3a^2+5){-1}(-3a^2+5) \end{aligned}$ $\begin{aligned} &=-9a^4+15a^2+3a^2-5 \\\\ &=-9a^4+18a^2-5 \end{aligned}$